1. Field of the Invention
The present invention relates to a screw driver, and more particularly to a ratchet screw driver.
2. Description of the Prior Art
A typical ratchet screw driver is disclosed in U.S. Pat. No. 5,687,820 to Lin and includes a driving stem that is secured to the handle and may not be easily disengaged from the handle for being replaced with the other driving stems of different configurations or sizes.
The applicant has developed an extendible screw driver which is disclosed in U.S. Pat. No. 5,732,606 to Chiang and which includes a flexible extension that may be extended outward of the handle for increasing the length of the driving stem. However, no ratchet mechanism is applied to the screw driver and the driving stem also may not be disengaged from the handle for being replaced with the other driving stems.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional screw drivers